Inventory control is a primary concern for product retailers so that excess and insufficient inventory situations are avoided. Within a mortar and bricks environment, inventory is controlled by counting existing inventory at physical locations. To facilitate this inventory tracking process, it is common to label products with data symbols such as for example bar codes that can be read by an optical scanner. Such optical technology, however, requires line-of-sight (“LOS”) between the optical scanner and the data symbols in order for the data symbols to be read. Unless products carrying such data symbols are well-aligned, automated reading of these data symbols is difficult to accomplish making the inventory tracking process onerous and time consuming.
In more recent years, radio frequency identification (“RFID”) tags have become commercially viable and have been used to replace data symbols in a number of applications. RFID tags provide the advantage in that a line of sight to the RFID tags is not required to read the RFID tags. Although the use of RFID tags provides this advantage over data symbols, problems exist with RFID tags. For example, increased distance between an RFID reader, also known as a balanced/unbalanced “balun” antenna, and the RFID tags adversely effects signal strength and reliability. As a result, it is often necessary to ensure the RFID reader is in close proximity to the products carrying the RFID tags in order for the RFID tags to be read. Depending on the environment, bringing the RFID reader into close proximity with the RFID tags can be a challenging task.
Also, even though a line of sight to RFID tags is not necessarily required to read the RFID tags, in some environments the use of RFID tags to label products has still proven to be ineffective. For example, when RFID tagged products are packed in boxes, cartons, vending machines or other product containing units, the product containing units are often “impenetrable” to the RFID reader. If the size of the product containing unit is large, some of the RFID tagged products may be simply out of range of the RFID reader. If the product containing unit holds a significant number of RFID tagged products that are tightly packed, proximate RFID tags may cancel one another out during reading (“referred to commonly as “metalizing”), inhibiting the RFID tags from being read. If the product containing unit includes or contains certain metals or contains certain liquids, the effective range of the RFID reader can be significantly reduced making reading of the RFID tags virtually impossible. As will be appreciated, the only way to track inventory in such environments is to open the product containing units, which of course is highly undesirable.
Whether using data symbols or RFID tags to label products, it will be appreciated that controlling inventory by scanning or reading the labeled products is much more difficult and in fact impractical in environments where inventory is dispensed through stocked vending or dispensing machines that are distributed over a large geographical area.
To deal with inventory control in these environments, service personnel are typically dispatched along service routes according to pre-set schedules so that the vending machines can be checked for inventory levels and proper operation. As will be appreciated, during a service route all vending machines along the service route are checked. In many instances, the checks reveal that the vending machines are operating properly and hold sufficient inventory. As a result, the checks are unnecessary. In other instances, the checks reveal that the vending machines have malfunctioned and/or are depleted of inventory, resulting in potential lost sales especially if delays exist between checks.
Also, in the case of vending machines it has in the past been difficult to confirm that transactions have been successfully completed. In some instances products are not properly dispensed even though they have been paid for. To deal with this problem, multi-faceted arrays have been incorporated into vending machines to sense the dispensation of product. While such multi-faceted arrays allow situations where paid for products are not properly dispensed to be detected, they are expensive and have proven to be only somewhat reliable.
In the medical supply environment, medical, surgical, biological and/or pharmaceutical supplies are stored in refrigerated dispensing units distributed throughout medical, research and/or educational facilities located at different geographical locations. In the past, dispatching medical supplies through these refrigerated dispensing units has been based on the honor system. Users removing supplies from refrigerated dispensing units are expected to list the removed supplies on charts posted on the refrigerated dispensing units so that supply usage can be tracked and costs assigned in the appropriate manner.
As will be appreciated, inventory control in this medical supply environment suffers similar problems to those encountered in the vending machine environment discussed above. Routine checks of all refrigerated dispensing units must be carried out to determine the inventory level and operating status of the refrigerated dispensing units. In many cases the checks are either unnecessary or late. The latter condition can be particularly problematic in the case where a refrigerated dispensing unit fails and the temperature within the refrigerated dispending unit rises to a point where the inventory is spoiled. Inventory shrinkage is also a problem in the medical supply environment. In many instances, users removing supplies from the refrigerated dispensing units fail to record accurately the removed items. As a result, costs for the missing inventory cannot be assigned. As will be appreciated, improvements in inventory control in environments where product is not readily accessible are desired.
It is therefore an object of the present invention to provide a novel supplementary antenna for radio frequency identification, to a system and method for tracking inventory and to a product containing unit including at least one supplementary antenna.